The aeromagnetic data of Otukpo (sheet 270) and Ejekwe (sheet 289) areas of the lower Benue Trough of Nigeria were interpreted quantitatively. The quantitative interpretation employed spectral analysis technique with the aim of locating specific basement depths to buried magnetic source rocks in the study area. First order polynomial fitting was adopted for regional-residual separation of the total magnetic intensity (TMI) map. The result of the spectral analysis indicates two depth source models; with depths to the deep sources varying from 2546.5 to 4177.3 m, having an average depth of 3058 m; while the depths to the shallow magnetic sources vary from 309.4 to 762.5 m, with an average depth of 527 m. The Otukpo area has greater sediment thickness capable of hydrocarbon accumulation than the Ejekwe area. This is supported by the presence of many intrusions at the Ejekwe area, with large lateral extents, indicative of over mature source rocks.